Active millimeter wave simulator for missile seeker evaluations

Abstract

An active millimeter wave simulator for missile seeker evaluations wherein a missile seeker generates seeker signals and transmits them in the direction of an array of active antenna elements. Range timing signals are delayed in a time delay circuit to simulate a range between the missile seeker and a target. The seeker signals as received by the active antenna elements are supplied to a millimeter wave spectrum analyzer for determination of their frequency. A computer receives the determined frequency and controls a millimeter wave source to generate simulated target response signals with that same frequency but delayed in accordance with the time delay signal. The computer controls a master target control circuit to select a triad of antennas in the antenna array and to generate a phase center in the triad generating the target response signals. The millimeter wave spectrum analyzer further determines the frequency of the target response signals. The computer compares the frequencies of the target response signals and the missile seeker signals and controls the millimeter wave source to ensure correspondence between those frequencies.

We claim: 
     
       1. In a passive simulator adapted for active mode missile seeker target tracking evaluations in real time wherein a missile seeker generates seeker signals having characteristic frequencies and a seeker timer signal associated with the seeker signals, an improvement comprising: means for delaying said seeker timer signal to simulate a range between the missile and said target;   means for generating target response signals simulating the reflections of said seeker signals from said target;   means for determining the characteristic frequencies of said seeker signals and for generating an output signal corresponding thereto; and   means responsive to said delayed seeker timer signal and said output signal for controlling said generating means to generate said target response signals having frequencies corresponding to the frequencies of said seeker signals and amplitudes corresponding to said simulated range from said missile to said target.   
     
     
       2. A simulator according to claim 1 wherein said target response signals are millimeter wave signals. 
     
     
       3. A simulator according to claim 2 wherein said generating means comprises: a millimeter wave signal generator for generating said millimeter wave signals;   a plurality of antennas coupled to said signal generator; and   means for selecting one or more of said antennas to transmit said millimeter wave signals.   
     
     
       4. A simulator according to claim 3 wherein said controlling means comprises: a processor;   a frequency control circuit for controlling said millimeter wave signal generator to generate said millimeter wave signals with frequencies corresponding to said output signal of said determining means; and   an amplitude control circuit for modulating said millimeter wave signals to have an amplitude simulating a selected range between said missile and said target.   
     
     
       5. A simulator according to claim 4 wherein said determining means comprises: means for receiving said seeker signals; and   means for analyzing said received seeker signals to determine the frequency thereof.   
     
     
       6. In a passive simulator adapted for active mode missile seeker target tracking evaluations in real time wherein a missile seeker generates seeker signals having characteristic frequencies and a seeker timer signal associated with the seeker signals, an improvement comprising: means for selectively delaying said seeker timer signals to simulate the range between the missile and the target;   means for generating target response signals having characteristic frequencies simulating reflections of said seeker signals from said target;   means for determining the difference between the characteristic frequencies of said seeker signals and said target response signals and for generating an output signal associated with said determined differences;   control means responsive to said delay seeker timer signal and said output signal from said generating means to generate said target response signals having frequencies corresponding to the frequencies of said seeker signals and amplitudes corresponding to said simulated range from said missile to said target; and   means for supporting said missile seeker in the path of said target response signals and for reflecting from said simulator any target response signals not received by said missile seeker.   
     
     
       7. A simulator according to claim 6 wherein said generating means comprises: a millimeter wave source; and   a plurality of antennas coupled to said millimeter wave source for selectively transmitting said millimeter waves and for receiving said seeker signals.   
     
     
       8. A simulator according to claim 7 wherein said determining and generating means comprises: a spectrum analyzer circuit; and   a switch coupled to one of said antennas and to said millimeter wave source for selectively supplying said seeker signals and said target response signals to said spectrum analyzer circuit, said spectrum analyzer circuit for generating a feedback signal corresponding to the differences and characteristic frequencies between said seeker signals and target response signals and for supplying said feedback signal to said millimeter wave source to control said source to adjust the characteristic frequencies of said target response signals to eliminate said frequency differences.   
     
     
       9. A simulator according to claim 8 wherein said control means comprises: an amplitude control circuit coupled to said millimeter wave source for receiving said millimeter wave signals and for varying the amplitude thereof in accordance with the range to be simulated, said amplitude varying in direct proportion to the simulated range between the missile and the target;   a master target control circuit for selecting one or more of said antennas to generate said target response signals and for changing the antenna selected to simulate movement of the seeker during the tracking of the target; and   a processor for controlling said master target control circuit, said delay means, and said switch to simulate the acquisition and tracking of the target by the seeker.   
     
     
       10. A simulator according to claim 9 wherein said supporting means comprises: a flight table for supporting said seeker; and   a planar surface angularly positioned in the path of said target response signals to reflect out of said simulator any target response signals incident upon said planar surface, said planar surface including an aperture for receiving said supported seeker to permit said seeker to receive said target response signals.   
     
     
       11. A simulator adapted for both active and passive mode missile seeker target tracking evaluations in real time wherein a missile seeker generates seeker signals having characteristic frequencies and a seeker timer signal associated with the seeker signals, the simulator comprising: an anechoic chamber adapted for passive mode missile tracking evaluations;   means for selectively delaying said seeker timer signals to simulate the range between the missile and the target;   means for generating target response signals having characteristic frequencies simulating reflections of said seeker signals from said target;   means for determining the difference between the characteristic frequencies of said seeker signals and said target response signals and for generating an output signal associated with said determined differences;   control means responsive to said delay seeker timer signal and said output signal from said generating means to generate said target response signals having frequencies corresponding to the frequencies of said seeker signals and amplitudes corresponding to said simulated range from said missile to said target; and   means for supporting said missile seeker in the path of said target response signals and for reflecting through an opening in said anechoic chamber away from said simulator any target response signals not received by said missile seeker.